package com.lagou.rpc.consumer.proxy;

import com.alibaba.fastjson.JSON;
import com.lagou.rpc.common.RpcRequest;
import com.lagou.rpc.common.RpcResponse;
import com.lagou.rpc.consumer.client.RpcClient;
import org.springframework.util.ReflectionUtils;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.time.LocalDateTime;
import java.util.Arrays;
import java.util.UUID;

/**
 * 客户端代理类-创建代理对象
 * 1.封装request请求对象
 * 2.创建RpcClient对象
 * 3.发送消息
 * 4.返回结果
 */
public class RpcClientProxy {

    public static Object createProxy(Class<?> serviceClass) {
        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
                new Class[]{serviceClass}, new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {

                        //1.封装request请求对象
                        RpcRequest rpcRequest = new RpcRequest();
                        rpcRequest.setRequestId(UUID.randomUUID().toString());
                        rpcRequest.setClassName(method.getDeclaringClass().getName());
                        rpcRequest.setMethodName(method.getName());
                        rpcRequest.setParameterTypes(method.getParameterTypes());
                        rpcRequest.setParameters(args);

                        //2.创建RpcClient对象
                        //此处来模拟负载均衡轮询模拟调用多个服务端中的一个
                        //根据 args 的哈希值与请求的时间秒数的逻辑与运算的值来负载轮询
                        int portHash = Arrays.hashCode(args) + LocalDateTime.now().getSecond();
                        //1 或者 0
                        int portDelta = portHash & 1;
                        //最终端口为 8081 或者 8082
                        int port = 8081 + portDelta;
                        RpcClient rpcClient = new RpcClient("127.0.0.1", port);
                        try {
                            //3.发送消息
                            Object responseMsg = rpcClient.send(JSON.toJSONString(rpcRequest));
                            RpcResponse rpcResponse = JSON.parseObject(responseMsg.toString(), RpcResponse.class);
                            if (rpcResponse.getError() != null) {
                                throw new RuntimeException(rpcResponse.getError());
                            }
                            //4.返回结果
                            Object result = rpcResponse.getResult();
                            int fromRpcPort = rpcResponse.getFromRpcPort();
                            Field fromPortField = ReflectionUtils.findField(method.getReturnType(), "fromPort");
                            if (fromPortField != null) {
                                fromPortField.setAccessible(true);
                            }
                            Object beanResult = JSON.parseObject(result.toString(), method.getReturnType());
                            if (fromPortField != null) {
                                ReflectionUtils.setField(fromPortField, beanResult, fromRpcPort);
                            }
                            return beanResult;
                        } catch (Exception e) {
                            throw e;
                        } finally {
                            rpcClient.close();
                        }

                    }
                });
    }
}
